Interaction Between AsHg and V Hg in Arsenic-Doped Hg1−x Cd x Te

Abstract

Arsenic-related defect complexes have been proven responsible for the charge-compensation effects in arsenic-doped Hg1−xCdxTe, but the underlying mechanism is still unclear. In this study, we systematically investigated the interaction between arsenic donor (AsHg) and mercury vacancy (VHg) versus the AsHg–VHg separation in arsenic-doped Hg1−xCdxTe using first-principles calculations. A new long-range interaction between AsHg and VHg is found, and the related binding energies and electronic structures are calculated to reveal its coupling mechanism. Our results show that VHg can increase the distortion of the lattice collaboratively with AsHg due to the different characteristics of AsHg and VHg in distorting the lattice. The relaxational enhancement as well as the electrical compensation of the AsHg donor is weakened as VHg moves away from AsHg, and the underlying mechanism is revealed. In addition, a set of defect levels in the band gap generated from the donor–acceptor interaction are also shown, and the origin of these levels is explored. The results of this work are important for theoretically explaining the characteristics of complicated defect levels found in experiments.